Sunday morning, David Gregory introduced former pizza executive Herman Cain to Meet the Press as the frontrunner in NBC’s latest GOP poll and as “the man of the moment.” Taken together, you can translate those two statements thus: political reporters pretty much have no choice but to cover Cain given his rise in the polls, but plainly believe that it won’t last (hence “moment”).

They may be right; they may not. But their guesswork is irrelevant. This all brings me back to my belief, especially this volatile primary season, that if the press is going to cover the horse race,* they should at least cover candidates on the basis of their demonstrated support, not on their often-incorrect guesses about who is “viable” in the long run.

*(They shouldn’t; at least at this point they should be covering the ideas that are battling it out in the primary. But I’m not kidding myself here.)

Patient Zero of this phenomenon this year is former Utah Gov. Jon Huntsman, who, as I pointed out back in June, has been lavishly covered by the press despite the lack of evidence that he can make Republican voters want him to be the President. When I snarked about this back in June, I got some responses that Huntsman needed to be taken seriously: because he has money, because he had recruited big-time campaign staff, because eventually primary voters would gravitate back toward a grown-up–the kind of pragmatic, reasonable man that journalists respond to–and it would be Huntsman and Romney.

Sure enough, since then Huntsman’s poll support has mushroomed–to a whopping 3% in the same NBC poll that Cain leads with 27%. (Try looking for Cain’s press clips back in June, when he was already running ahead of Huntsman, 15% to 1% in an Iowa poll, yet was called a “long shot” next to Huntsman’s “top-tier” candidacy.)

Back to Cain: since he’s risen to the lead in several polls in the past couple of weeks, the press has at least had to take him and his proposals seriously, particularly his 9-9-9 tax plan. (See my colleague Stephen Gandel’s economic assessment of it here.) And Gregory questioned Cain on it aggressively, getting him to concede that some people–particularly poorer people who spend most of their income to feed their families–will end up paying more in taxes in a system that adds a 9% national sales tax.

Cain’s responses were sometimes baffling: the price of bread, he argued, would go down under his plan because of “competition” among bakers. (Who apparently get along without competing whatsoever under the current tax system?) They were sometimes contradictory. (He defined “stupid” people as “People who are so dug in with partisanship and partisan politics”–about a minute after he said he believed liberals are deliberately trying to destroy America.)

But they were not necessarily harmful politically. One advantage that Cain has had–especially compared with flameout Rick Perry in the recent debates–is his ability to speak directly, off the cuff, and make an advantage of simplicity and even of his lack of knowledge of details.

For instance, 9-9-9 would pass, he said, “Because the American people understand it, the American people are embracing it.” The latter may be debatable, but it does seem to be an advantage among his growing legion of voters that he has a plan that is drastic yet can be summed up simply. And that he talks about it simply: he was offering specifics and a big change, he said, while his opponents were offering “generic” economic solutions. (Romney’s largely warmed-over “59-point plan,” Perry’s mumble mumble mumble energy.)

What’s struck me most about Cain, though, is his unhesitant willingness to admit what he doesn’t know. With Gregory, he affably said he did not know what neoconservatism is; this after an earlier interview where he said he did not know the leader of Uzbekistan, or, rather, “Ubeki-beki-beki-beki-stan-stan.” I have to wonder if this is a conscious departure from the strategy of Sarah Palin, to bluff her way through a stumper like a kid called on by the teacher at the worst possible moment.

Can Cain use that bluntness as an advantage from here through the convention? Will voters eventually expect him to give correct answers—or, for instance, not to explain away comments like his call for an electrified border fence as a “joke”? I don’t know, but neither do the handicappers of the political press, which is why they need to catch up and take Cain—including his “jokes”—dead seriously.